Glass containers are conventionally formed in a machine that comprises a plurality of sections, in each of which there are one or more blank or parison mold cavities and transfer mechanisms that are synchronized with each other. This machine, called an individual section or IS machine, receives glass in the form of discrete mold charges or gobs. Molten glass from a furnace is cut into individual gobs, which are fed to a gob distributor. The purpose of the gob distributor is to distribute the gobs to the individual sections of the IS machine in the appropriate sequence in such a way that the glass gobs simultaneously arrive at the mold cavities in each section in sequence. U.S. Pat. Nos. 3,585,017 and 3,597,187, and patents noted therein, illustrate the general technology.
U.S. Pat. No. 2,859,559 discloses a gob distributor construction in which a scoop is disposed beneath a gob shear mechanism for receiving molten gobs in sequence, and is coupled by a shaft to a motor for feeding the individual gobs to spaced chutes or troughs. Each trough leads to the initial mold cavity of an associated section of an IS machine. Each cavity of the IS machine has an associated trough, and the scoop feeds gobs to the individual troughs in an appropriate sequence. U.S. Pat. No. 3,597,187 discloses a gob distributor in which a plurality of scoops each have an upper end disposed beneath an associated gob discharge, and a lower end disposed to swing through an arc adjacent to a corresponding plurality of troughs. Each scoop is carried by a scoop support frame, which is in turn is coupled to a drive shaft. The multiple drive shafts are coupled to a gear transmission drive, in which the shafts are conjointly driven through associated gears by a single motor. Although this transmission drive arrangement maintains proper synchronism among the scoops, a problem arises when it is desired to change the number of scoops. An entirely new transmission drive is required.
A general object of the present invention is to provide a glass gob distribution system and method in which gob distribution scoops may be readily added, deleted or inactivated without requiring redesign or replacement of the entire scoop drive structure. Another and more specific object of the present invention is to provide a glass gob distribution system and method for a multiple-cavity IS machine in which the scoop for each cavity is mechanically independent from the scoops for the other cavities, and in which scoop position and motion profile may be readily electronically adjusted independently of the other scoops of the distribution system.
A molten glass gob distributor for a glass article manufacturing system in accordance with the present invention includes a plurality of gob discharges, and a plurality of scoops for receiving gobs from each such discharge and distributing the gobs among a plurality of troughs or chutes leading to associated molds in a multiple-cavity IS machine. Each scoop is mounted to rotate about a fixed axis with the upper end remaining positioned beneath the associated gob discharge while the lower end swings through an arc adjacent to the associated troughs. A plurality of electric motors are individually coupled to each associated scoop for selectively and individually rotating the scoops. The electric motors are all connected to a motor controller for synchronizing operation of the motors and rotation of the scoops to each other and to operation of the forming machine. Preferably, the motors comprise electric servo motors each individually coupled to a single associated scoop, and the motor controller comprises an electronic servo motor controller operatively coupled to each servo motor and synchronizing operation thereof by means of a synchronizing input from the forming machine.